I need to plan an investigation to find the lowest temperature that kills all the yeast cells in a suspension of either dried or fresh bakers yeast
we are provided with-
10% suspension of yeast
10% soloutions of sucrose or glucose
1.0% methylene blue soloution
If the yeast respires and uses oxygen the methylene blue will go from blue - colourless. You need to make up suspensions of yeast in the sucrose and add some methylene blue. Keep tubes at different temeperatures and look for the lowest temperature at which the methylene blue remains blue (i.e. no respiration, so yeast is dead).